Patent Literature 1 discloses an engine automatic stop control that performs an idle stop control while securing a required air conditioning performance. The idle stop control stops an engine when the engine comes into an idle state.
Patent Literature 1 teaches that a temperature shift of an engine cooling water over time after the engine is stopped is estimated, and then a stop condition to stop the engine is set based on the estimated temperature shift. The engine is started automatically based on an air outlet temperature when the engine is stopped and an air conditioner is operated. The air outlet temperature is a temperature of air flowing out of the air conditioner.
Thus, a heating operation can be performed using heat, which is generated in the engine, by starting the engine before a passenger feels cold.